New York City Inferno (1978)

Jerome, a Frenchman, arrives in New York from Paris with only one idea in mind: to find his lover Paul, 'swallowed' by the New York S&M gay life. Encounter after encounter, Jerome will delve into the leather pit...
Somehow enjoyable gay hardcore flick, even if you're not gay. Let me name the ways... Our protagonist has a great pornstache, enough to make a man sweat and a woman wet. A soundtrack completely dominated by The Village People. Weird sex, with animal carcasses, in shitty bathroom stalls all over the city and a final great bizarre gay SM orgy in some sleazy, grottty club where the patrons where pig and skull masks, dance around in leather, fist each other, have glory hole trains and engage in assorted other delightful activities.